I want to create knowledge bases of a brand which contain all the information that is relevant to the brand. This would comprise creating of various entities and subentities. You are currently given the sub_entities of a particular entity. 

Your task is to carefully go through this list and add another field 'precursor' in each of these, it's value would be a comma separated list of other keys that need to be populated first before creating KBs for this particular key. 

MAKE SURE THERE ARE NO CIRCULAR DEPENDENCIES WHILE POPULATING THE PRECURSOR FIELDS.

The categories below are about: {key_info}

Sub Entities:
{sub_entities}

Output the modified sub entities JSON which has the 'precursor' field popualted. Do not modify anything else in the JSON. 
Ouput only this modified JSON and nothing else.